import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

/**
 * 实现一个自旋锁
 */
public class SpinLockDemo {
    AtomicReference<Thread> atomicReference = new AtomicReference<>();

    public void myLock() {
        Thread thread = Thread.currentThread();
        System.out.println(Thread.currentThread().getName() + "\t come in");

        while (!atomicReference.compareAndSet(null, thread)) {

        }
    }

    public void myUnlock() {
        Thread thread = Thread.currentThread();
        atomicReference.compareAndSet(thread, null);
        System.out.println(Thread.currentThread().getName() + "\t invoked myUnlock");
    }

    public static void main(String[] args) {
        SpinLockDemo spinLockDemo = new SpinLockDemo();

        new Thread(()->{
            spinLockDemo.myLock();
            try {
                TimeUnit.SECONDS.sleep(3);
                spinLockDemo.myUnlock();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }, "AA").start();

        new Thread(()->{
            spinLockDemo.myLock();
            spinLockDemo.myUnlock();
        }, "BB").start();
    }
}
